how to replace my original index.html with one created in bootstrap studio?

I have recreated my website in bootstrap studio and the new page is name the same as the original file, but i see in filezilla the extension is .bsd. how do i replace my old page with the new one created in bootstrap studio and how do i upload it via filezilla?

many thanks in advance

There are no .bsd files exported from BSS. You get full HTML, CSS and JS files on export so you're not exporting it doesn't sound like. Sounds like you're trying to upload the .bsdesign file maybe? You need to export your website in order for the correct files to be available. Put a folder on your desktop to export to (or wherever you want it to be) and then set up the settings of your project with an export location to that folder. Save those settings then hit export at the top or on the settings window (both do the same thing).

Now all your files will be within that folder, upload the "contents" of the folder you created which will include a folder named "assets" and your html pages.

Many thanks your a star, love the software. hope to learn a lot more as i use it more.

You're quite welcome, have fun with it!