Here’s a few tips.
Remember every hole is slightly different, so don’t simply repeat the same thing over. Vary the main techniques involved a little. For example you might try moving your tongue to a slightly different angle, drop your jaw a little, breath from further back in your throat or try going for the bend slowly etc..
Then when you do hit the bend on any given hole, repeat it 10 or more times immediately, to program the memory!
The other thing is to keep in mind is that the 2 and 3 holes can produce multiple notes when bending (this is covered in detail in step #7) so any bend on those holes at first will do.. to get up and running.
It can take a little while, regular everyday practice is the key!