No secrets, Cathy, just like anything else worthwhile: a learning curve.
There have been a number of discussions on here about what to use when starting out and, just like with family history apps, people will recommend what they themselves use. I compare it to carpentry: all brands have most of the same basic tools; it's a matter of finding what works for you.
But, briefly, I think most people on here use:
GIMP, which is free but is not easy to learn;
Photoshop Elements, a cutdown version of Photoshop, which costs about as much as a tank of fuel and is relatively easier to learn;
Photoshop itself, which is still considered the industry standard; but it is relatively expensive, requiring ongoing payments rather than a straight-out purchase.
Some restorers also use additional apps to increase the functionality of their main one.
I use Photoshop Elements (with very occasional assistance from other apps) and would recommend it for beginners. (I started with it in 2017.)
Now, wait for other people’s opinions.

Beware of one thing: it can become very addictive.
Peter