Questions & Answers about Přijdu přesně v deset.
Because přijdu comes from the perfective verb přijít. In Czech, perfective verbs do not normally have a true present meaning. Their present-form endings are used to express the future.
So:
- přijít = to come / to arrive (perfective)
- přijdu = I will come / I will arrive
If you wanted an ongoing or habitual meaning, Czech would use the imperfective verb přicházet instead.
Přijdu is:
- 1st person singular
- from přijít
- perfective
- future in meaning
So it literally means I will come or I will arrive.
The ending -u tells you the subject is I, which is why Czech does not need the pronoun já here.