It is suggested that learning pads is relatively simple. Small companies use pads to draw pcb, powerlogic/orcad to draw circuit, and large companies use cadence's orcad+allegro software. Their price is about 10 times, tens of W, hundreds of W Cadence. The commonly used pads are pirated, and the pirated industry is very easy to use, which may also be a reason. Easy to operate: it may be more convenient for small things to use pad, and the concept of what you see is what you get is still thoroughly implemented. Allegro is more rigorous, there are more things to know, and what you see may not be available. Pads are used for low-speed RF and allegro is used for high-speed RF. As for learning resources, you can search everything online, and you will find it. What you learn depends on how you use them. I suggest learning pad simply. Allegro is a bit complicated. Just watch pads for three days. I have studied Allegro for three months, but of course there is a difference in proficiency and depth. Personally, I think the difficulty coefficient is about 1: 3.