GST Rules for Fresh Vegetable and Fruits Online Marketplace

Hello,

I have GST registration of Proprietorship Firm in Rasjasthan. Now Planning to start website and Mobile App for Multi Seller Vegetable and fruits marketplace. i will charge a percentage of order value as commission from vendors. IF sellors are from other states, for example from M.P or U.P than

1. Will i have to take seperate GST reg. in those states?

2.  will sellors need to register for GST for fresh Fruits and Vegetables selling on my website?

3. I will charge a percentage of order value from sellors. How much Gst will i have to collect on this commission? This will fall in SERVICE category?

Thanks in advance.