How do you say that someone "Is going"?
How would you way that someone "Is going" a la parque? What is the present participle of "ir"?
Verbs of motion like "ir", "irse" and "venir", for example, do not usually get put in present progressive.
In other words, you usually do not use the present participle (yendo, viniendo, etc). So, "voy" can be translated as "I go" or "I'm going", like "vengo" can be translated as "I come" or "I'm coming".
For "ir", the present participle is "yendo", but "Voy al parque" is used rather than "Estoy yendo al parque".
Hello. Mariannge is correct as usual. I just thought I'd add that we have a great resource here on SpanishDict that might interest you. If you type any Spanish verb into the dictionary search box at the top of the page, and then scroll down to the bottom of the entry, you will see a chart with lots of conjugations. You can click on "Complete [word] translation" to see all the verb forms. Here it is for ir.
Voy al parque (I'm going to the park)
Vas al parque (You are going to the park)
Va al parque (He is going to the park)
I should add that the present progressive could be used, but it doesn't mean "I'm going" in general, I feel like it means something like "I'm on my way at this very moment."