Recommendations for basic AI/path scripting for shoot 'em up enemies

I actually asked about path finding earlier. And i've discovered that what you need to do is first get a straight path to the player's position. Then, if there are objects within that path, make it find a route around it (a bit more complicated, but you should beable to find something on this topic). Now, take in elevation, is the enemy on a higher elevation than the player? or vice versa? If so, is there another way down like stairs or a ramp? etc. Just try out different methods for each thing one by one, dont go all out trying to figure out a simple AI/path finding script. Factor in everything. Google is your friend <3