僕は行きます。 Boku wa ikimasu. 'I'm going.'
全然分かりません。 Zenzen wakarimasen. 'I don't understand at all.'
子供 kodomo 'children'
僕 boku 'I, me' (used by male speakers)
全然 zenzen 'at all' (always used with a negative verb)
分かる wakaru 'understand'
Most verbs ending in -eru or -iru are RU Verbs, but there is a number which are U Verbs. Watch out for these! Two common ones are hairu 'enter' -> hairimasu and kaeru 'go home' -> kaerimasu.