AMPscript code to pre-fill and update based on a form [closed]

I need help with the pre-fill and update part of this:

1. Create four Data extensions:"Subscribers" with subscriber attributes: SubscriberKey, FirstName, LastName, EmailAddress, PhoneNumber, BirthDate, Gender, Country, LastUpdated Date

• "Newsletter" with information about newsletter subscribers: SubscriberKey, Status (subscriberd/unsubscribed), LastUpdatedDate
• "SpecialOffers" with information about newsletter subscribers: SubscriberKey, Status (subscriberd/unsubscribed), LastUpdatedDate
• "Events" with information about newsletter subscribers: SubscriberKey, Status (subscriberd/unsubscribed),
LastUpdatedDate

1. Fill data in above data extensions with dummy data
2. Create a simple email with a link at the bottom that says „Update your preferences" which takes the subscribers to the Custom Profile & Subscription Center you are going to build.

Create a Custom Profile & Subscription center on a CloudPage with the following fields:
FirstName (text field),LastName (text field),EmailAddress (text field),
PhoneNumber (text field),
BirthDate (date field),
Gender (drop-down list with options male/female/prefer not to say), Country (drop down or text field)Three checkboxes for subscription preferences:

• Newsletter,
• Special Offers,
• Events. Any changes to attributes should be updated in the Subscribers Data Extension. The checkboxes for each communication type should be reflected by a status field in a relevant Data Extension (subscribed/unsubscribed). For each form submission, LastUpdatedDate needs to be written into a Data Extension.Make sure the form is pre-populated with data when a subscriber visits the website.

The code I’ve tried:

    %%[  VAR @SubscriberKey,       @rows_subscribers,       @row_subscribers,       @firstName,      @lastName,       @email,       @phone,       @gender,       @country,       @iSET @SubscriberKey = RequestParameter("SubscriberKey")SET @SubscriberKey = toNumber(@SubscriberKey)SET @rows_subscribers = LookupRows("Subscribers", "SubscriberKey", @SubscriberKey)  IF RowCount(@rows_subscribers) > 0 THEN    FOR @i = 1 to RowCount(@rows_subscribers) DO      SET @row_subscribers = Row(@rows_subscribers, @i)      SET @firstName = Field(@row_subscribers, "FirstName")      SET @lastName = Field(@row_subscribers, "LastName")      SET @email = Field(@row_subscribers, "EmailAddress")      SET @phone = Field(@row_subscribers, "PhoneNumber")      SET @gender = Field(@row_subscribers, "Gender")      SET @country = Field(@row_subscribers, "Country")    NEXT @i  ENDIF  /* Newsletter */  VAR @rows_NewsLetter, @row_NewsLetter, @NewsletterStatus  SET @rows_NewsLetter = LookupRows("Newsletter","SubscriberKey", @SubscriberKey)  IF RowCount(@rows_NewsLetter) > 0 THEN    FOR @i = 1 TO RowCount(@rows_NewsLetter) DO      SET @row_NewsLetter = Row(@rows_NewsLetter, @i)      SET @NewsletterStatus = Field(@row_NewsLetter, "Status")    NEXT @i  ENDIF  /* Special Offers */  VAR @rows_Offer, @row_Offer, @offerStatus  SET @rows_Offer = LookupRows("SpecialOffers","SubscriberKey", @SubscriberKey)  IF RowCount(@rows_Offer) > 0 THEN    FOR @i = 1 TO RowCount(@rows_Offer) DO      SET @row_Offer = Row(@rows_Offer, @i)      SET @offerStatus = Field(@row_Offer, "Status")    NEXT @i  ENDIF  /* Events */  VAR @rows_Event, @row_Event, @eventStatus  SET @rows_Event = LookupRows("Events","SubscriberKey", @SubscriberKey)  IF RowCount(@rows_Event) > 0 THEN    FOR @i = 1 TO RowCount(@rows_Event) DO      SET @row_Event = Row(@rows_Event, @i)      SET @eventStatus = Field(@row_Event, "Status")    NEXT @i  ENDIF  /*experimental*//*  set @subscriberKey = RequestParameter("subscriberKey")set @firstName = RequestParameter("FirstName")set @lastName = RequestParameter("LastName")set @emailAddress = RequestParameter("EmailAddress")set @phone = RequestParameter("PhoneNumber")set @gender = RequestParameter("Gender")set @country = RequestParameter("Country")UpdateData( "SubscriberKey", @subscriberKey, "FirstName", @firstName, "LastName", @lastName, "EmailAddress", @emailAddress,"PhoneNumber", @phone,"Gender", @gender,"Country", @country)UpdateData("Newsletter", 1 ,"SubscriberKey", @subscriberKey,"Status",@NewsletterStatus)UpdateData("SpecialOffers", 1,"SubscriberKey", @subscriberKey,"Status",@offerStatus)UpdateData("Events", 1,"SubscriberKey", @subscriberKey,"Status",@eventStatus)  */]%% Also in email studio:     %%[VAR @subscriberKey, @cloudPageURLSET @subscriberKey = AttributeValue("SubscriberKey")SET @cloudPageURL = CloudPagesURL('3382','SubscriberKey',@subscriberKey)]%%

Update your preferences!