In Russian language, the infinitive is used in the following situations:

Мы бу́дем рабо́тать.
(We shall work.)

Мы на́чали разгова́ривать.
(We have started talking.)

Он продо́лжил рабо́тать.
(He continued to work.)

Она́ ко́нчила чита́ть.
(She finished reading.)

Мы гото́вы встре́тить госте́й.
(We are ready to meet the guests.)

Вам ну́жно прие́хать.
(You need to come.)

Им не́куда пое́хать.
(They have nowhere to go.)

Мы пое́хали ката́ться на лы́жах.
(We went skiing.)

1. To construct compound future tense
2. In conjunction with the present tense verbs to designate the beginning, continuation or ending of an action
3. In combination with the words до́лжен (must), рад (glad), гото́в (ready), обя́зан (obliged), наме́рен (intended)
4. In combination with adverbs and adjectives
5. In combination with such verbs of motion as идти́ (to go by foot), ходи́ть (to walk), е́здить (to go by vehicle), лете́ть (to fly), пое́хать (to go by vehicle)

Note: The infinitive is never used with the verb зна́ть (to know).

Подготовка к TORFL в Алматы

Source: masterrussian.com