Looking for help with crocheting a basic baby blanket?

Literally, miss (or skip) the next half double crochet stitch, chain 2 space, and half double crochet stitch. You will be skipping a stitch, a space, and a stitch. The chain will take you to the next point where you do an hdc stitch.

The instructions are leading you to create those "holes" that form the diamond shapes. You hdc in several hdcs, then you chain 4, skip the next hdc, the next chain space, and the next hdc, then you hdc several times and skip again. On the next row, you'll also be making holes, and you'll start filling in the holes from the previous row. The rows of holes you create "move" on an angle to intersect other rows of holes and create the diamonds.

Any time you have instructions that are in this format,

Miss next (half double crochet, chain 2, half double crochet)

with the word "miss" or "skip" used followed by stitch instructions in brackets ( ) [ ] { }, it generally indicates you should skip/miss everything located within the brackets.

it's telling you to miss the next (hdc,ch2, hdc) all together

the chain 4 will create another space over and to the side of the one on the row below thus creating the pattern