Links are when you completely finish one normal and follow it up with another normal after the first move finishes its recovery frames. An example for Seth is cr.mp st.mp. The timing is tight but definitely easier than previous titles due to SFV having a small buffer in which to input the next move and still have it come out. To test this, set the training dummy to block after first attack. If you successfully “link” cr.mp into st.mp the dummy will take a 2 hit combo. If the dummy blocks the second hit, you were too late on your timing. Too early and the st.mp won’t come out at all.

Cancels are when you input a special move before the recovery frames finish on another move. You will mostly cancel a normal into a special such as cr.mk xx 214lk but there are circumstances with some characters where you can cancel a special move into another special move