There are a few ways to migrate and move assets into your Instadapp account on Polygon. If you need to migrate positions between Instadapp accounts you will need to have an account on both Ethereum and Polygon. If you need help creating an account on Polygon please see
Migrating Assets across Instadapp Accounts
The first method is to use the Matic Bridge built into Instadapp; this will migrate your balances from one Instadapp account into another Instadapp account on Polygon.
The second method is to use the Migration Bridge which will migrate both assets and liabilities. This can be used to migrate between protocols on different chains.