99% of combos are applied in either whiff punishes, frame traps or wake up extensions for Ryu.
You generally practice combos in training to get the muscle memory for the timing down, you won’t necessarily always apply them raw in matches.
Pretty much everyone can block Ryu’s normal high/low mixups without much trouble since he doesn’t have a combo-able or instant overhead (few people do), but you can still sneak those in or do tick throws to get damage or set ups respectively.
In most cases, if you safe jump a wake up SRK you can punish them as they’re landing with either a sweep into another wake up setup or any of your set combos, it’s a little risky to punish Ken’s Jab SRK since I believe it has very few frames (3) of landed recovery but you can easily do it to Ryu or Akuma (5).
For frame traps, Ryu’s training room combo of cr.mp,cr.mp,cr.hk is excellent for baiting a counter hit, as there’s only 4 frames of start up for each of the cr.mp’s, and it puts the opponent at -2 on block (or conversely has ryu at +2), meaning that the only possible counters are 1 or 0 frame moves (eg. Zangief’s SPD, Raging Demon super) , so anyone trying a 3 frame lp/lk to counter a blocked cr.mp will get hit for a counter hit by the second cr.mp into a sweep.
Another trap, with Ryu’s cr.lp x3, cr.mk, fireball can form a tight block string from the ranges where the cr.mk isn’t landed near the tip and is an excellent hit confirm if the opposing player pushes any buttons in the sequence they’ll get hit (excluding again 1 and 0 frame moves, get the notion, don’t try and frame trap Zangief) and the fireball can be FADC’d into any combo extensions.
For wake ups, against characters without 3 frame DPs you can go for ambiguous cross ups with Ryu’s fj.mk/lk (if you space this properly pressing lk leaves you in front and mk hits behind), tatsu cross ups (air and grounded), or safe jump option selects, all of these can lead to big comboes.
You can also of course, focus obvious jump ins or sweeps for the crumple into easy comboes.
As a Ryu player, you pretty much have to read all of Air’s amazing articles on how to play Ryu.