Similar kits are still around: https://www.amazon.com/dp/B08FCS39BL
This kit is the best way to get started on L-Band.
https://www.amazon.com/Nooelec-Active-Inmarsat-Reception-Bundle/dp/B08FCS39BL
You need to add a v3 RTLSDR (I like the silver one the best - you can use a USB powersupply to power the LNA if you get the silver dongle), but if you get the kit, and are not sure how turn on the BiasT in your SDR software, then best to get the Smartee since it has the BiasT turned on and so it will just be a plug and play solution. Note, get the Smartee, not the SmarteeXLR as you don't need the extended range and I have found its performance less than good at L-Band.
Once you get the hardware set up (hopefully you have a window that looks toward the satellite - if not, don't spend the money getting the hardware - just use https://app.airframes.io/ to look at the messages). You just need the software. I use SDR# with the VFO plug in, a licensed copy of VAC (Virtual Audio Cable) and Jaero.
With that, you should be up and running.