For some reason, I was not able to download the Oracle Client along with my Toad download. So instead I installed Oracle Client on my pc as a separate download. Toad will not allow me to browse to that Oracle home.
We do not package the Oracle client into our installer bundle - we just provide links for you to go get it. Licensing issues - you must pay for most Oracle clients that most people prefer to use - so better to stay clear of that by just providing links.
Once you install Oracle client - if it’s fat/full client installer which creates windows registry entires then toad would see it. If you just downloaded the instant client which is just a tiny zip file to unzip - read the Oracle instant client install instructions. You must create a windows env var called TNS_ADMIN and you must include the dir where you unzip in your PATh env var. Oracle spells all this out in the readme and install instructions - and I’ve blogged about it on toad world a couple times to boot.