You've already seen that when telling people what to do, the verb changes a little. Here's the pattern for turning ‑ar verbs like tentar into commands!
subject
verb (tentar)
você
tente
tu
tenta
vocês
tentem
And here are the forms for ‑er verbs like escrever.
subject
verb (escrever)
você
escreva
tu
escreve
vocês
escrevam
Tentem fazer isso mais uma vez.
Try doing that once more.
Help‑us!
When giving commands, small words like me and nos are attached to verbs with a little dash.