For selecting the vendor on the Vendor list page, the user has to click on that particular vendor line. The blue highlighted line shows the selected line. Please find below the screenshot for your reference.
For selecting multiple vendor lines, click on three dots after the vendor No. and then click on Select More from the drop-down list. Please find below screenshot for your reference.
Shortcut Keys:
- Shift + Up Arrow Key
- Shift + Down Arrow Key
I hope it will resolve all your concerns.
Thanks.