It is no more complicated than placing this phono stage "preamp" a device between your TT out put RCAs and the input into an aux on your reciever. That's all there is to it.
Again buy a phono preamp connect you tt output to the phono preamp's input the connect it's out put with a second set of interconnect RCAs to your reciever's aux input. When you want to play your TT switch your reciever to the aux input you chose play and enjoy.
As for improvements thats another matter.
You could decide to go with an entry level "High End" TT like a used Rega or Music Hall. Hopefully with a decent cartridge included probably a MM. Then use a well regarded phono stage (preamp) like a Graham Slee for instance, amongst many other choices. Use your reciever set up for now and see if that improvement satisifies you.
Unfortunately you are going to have to immerse yourself in basic modern day analaog to guide yourself more accurately. It is some work but you will get it after a while don't fret.
Again buy a phono preamp connect you tt output to the phono preamp's input the connect it's out put with a second set of interconnect RCAs to your reciever's aux input. When you want to play your TT switch your reciever to the aux input you chose play and enjoy.
As for improvements thats another matter.
You could decide to go with an entry level "High End" TT like a used Rega or Music Hall. Hopefully with a decent cartridge included probably a MM. Then use a well regarded phono stage (preamp) like a Graham Slee for instance, amongst many other choices. Use your reciever set up for now and see if that improvement satisifies you.
Unfortunately you are going to have to immerse yourself in basic modern day analaog to guide yourself more accurately. It is some work but you will get it after a while don't fret.