TWRP is not installing...

I'm not familiar with Samsung but are you installing it in the right adress?

Remove auto-restart on odin and restart normaly when flash complete. Then boot str8 to recovery, twrp will patch the main recovery.

I managed to install it but my case was not common. All the physical buttons of my cellphone stopped working so I couldn't even boot into recovery, I had to do a lengthy process which involved the use of multiple software.

Odin is kinda annoying, sometimes you need a specific version of Odin in order to get it to work but there are too many other variables that can interfere with an successful installation. Your best bet is an Android specific forum, like the Android subreddit https://www.reddit.com/r/Android/ or even better that XDA forums https://forum.xda-developers.com/

The community there tends to be helpful and they are experts on this

Not the answer you look for but it is all I can offer

J7 has a locked bootloader.

Tupperware Remix Party?

I flash the recovery on my phones via fastboost.
Look if it works for your phone too.
Quite easy to do, just need to boot on fastboot and check if your device is recognized using

• fastboot devices

if yes

• fastboot flash recovery recovery.img
• fastboot reboot

PS: using tools like this one and adb works better on Linux

What I usually do to my phone:
Unlock bootloader.
Root it.
Flash Recovery.
Flash ROM.

Depending on the phone, you should use CWM (Clockwork Mod Recover) and then TWRP if you can't set TWRP the first time.
Fastboot also works via USB flash

XDA that's almost all you need

Bump

You gotta disable the automatic reboot, and reboot manually after you're done straight into recovery. Then you do the magic from there.

Or at least that's how I fixed it in the past, I haven't needed to root for a long time. The last thing I needed it for was adblock and now I've got that on the network level instead so I don't need it on my phone.