Allowing Data Input on one tab, but "Read-Only" on all other tabs

Hello,

I have built an Excel form to submit a lamp audit from a commercial building. There are three tabs:

1. Instructions - to educate sales partner on how to exactly fill out each field
2. Lamp Audit Page - input data collected from site (lamp wattage, fixture type, quantity, etc)
3. ZIP File Help - tutorial on how to ZIP photos and electric bills

I want the "Instructions" and "ZIP File Help" tab to be read only, I do not want sales partners to edit any text or photos on these tabs BUT I need them to be able to insert data in the "Lamp Audit Page"

Any help on how to make certain tabs read only?

Thanks,

Alessa