Powerapps - Create a record with data from a new form and a gallery

Question

in my app I'm a bit stucked on understanding how to build a record, don't know submitting it on a SP list or in a collection and then in a SP list, with a part of data from a new form and second part from a gallery (already connected to a collection).

In my screen at the beginning I have a new form used to get some personal data (eg. name, surname, VAT code, client name ecc), after clicking continue button a gallery with a list of all available product that can be choose (1 or more) with a select box (here the data are product name and product code).

My need here to is to understand how to collect these data from both items into record (1 record if the n. of product selected is one otherwise 1 for each product) and save them into  a SP list

Many thanks