This plane has a similar layout to the current Stanley SB4 (it has had various names over the years) and the "Windsor Design" No. 33 plane sold by Harbor Freight in the US.
The mechanism in these planes is essentially what is used in most modern spokeshaves, so searching for tips on how they are adjusted would bring up much more advice. But it's essentially very simple:
- you withdraw the cutter by screwing the two nuts one way (upwards)
- you advance the cutter by screwing the nuts the other way (towards the sole)
- to move the cutter laterally if needed (that is, move one corner up or down to change the angle of the cutting edge) you adjust only one of the two nuts.
In addition to the above generally with mechanisms like this the advice is to slightly loosen the bolt that holds the top cap in place, to more easily allow for the blade to be moved, then after the adjustments are done you tighten the cap back down again to ensure the cutter doesn't shift in use.
Not a good plane
Sorry to say it but unfortunately this is the case, so I hope you don't have hopes to be able to do fine work with it.
In recent years the Windsor Design no. 33 has been made fun of online quite a lot and the Stanley version before that has been reviled for decades, and has actually been called the worst plane ever made*.
So the adjustment mechanism is already considered very poor for a plane, but in addition to that notice there is one major difference with the HPL01300 compared to the above two planes, it has a body made from bent steel, not machined cast iron which is very much stiffer and stronger.
All planes with thin steel bodies like this are cheap tools intended for only the most basic or roughest work — more construction site than anything.
*This is not true to be honest, and it represents an unfair double standard. Although compared to even a mediocre Bailey-pattern plane they are a definite step downwards with careful setup they can be made to work quite well — at least as well as simpler block planes that have no adjustable mouth or inbuilt lateral adjustment, which aren't heavily criticised compared to their (much better) cousins which do have those features.