That’s a mag mount. It has three magnets to make it stick to steel. It costs a lot more than a regular mount, although it appears to come with a cable, so there’s that. You can just get a regular old lip mount for a tree or rain gutter and then bolt it on avoiding the extra cost of a mag mount.

The connector on the mount you linked is a different style. The UV5R uses an SMA male connection if memory serves (please verify before ordering) and the comet antenna uses a NMO connector. So you need an adapter that goes NMO to PL-259 adapter for the antenna to the mount you linked and then a PL-259 to SMA female for the radio. The whip antenna I linked uses a SMA female adapter so you would need two PL-259 to SMA adapters to use with that mount, one for the antenna and one for the radio. I think the radio one needs to be female, but please verify (I know, confusing. Right?).

You could always get this thing. I haven’t used one but I’ve heard decent things about it. You just toss it up into a tree and then attach it to your radio. You’ll need an adapter for that too. According to someone on Amazon you will need a UHF Female SO-239 to a SMA female adapter extension cable RG'-316 6" long. You would only need one adapter for that.

You can try picking up some chatter without any fancy antenna setup. Find a local repeater that looks like it has active club members and tune your radio to that. Then go outside and see if you hear anything. You can drive to the top of a hill or an open area to get better reception. I’m able to pick up a GMRS repeater on my UV5R that’s over ten miles away across the lake and 1.5 miles through residential neighborhoods.

Better yet, email a club you find and ask them for help listening in. Hams love helping people unless you’re unlucky enough to find an Elmer. If he’s rude just find someone else. You may end up getting a ton of guidance specific to your area and maybe even make a friend in the process. Ham radio is all about communication, so reaching out to people either over the air, over the internet, or through the postal service is part of the fun.