Compared to Romance languages, Czech has a very simple set of tenses. They are present, past, and future.
Past is used in almost all instances of past action, and replaces every past tense in English (past perfect, imperfect, pluperfect, etc.). The past tense is usually formed by affixing an -l- on the end of the verb, sometimes with a minor (rarely significant) stem change. After adding the -l-, letters are added in order to agree with the subject (-a for feminine, -i or -y for plural).
The present tense is precisely the same as in English. It is also used in cases where one would say, for instance, "I have been doing this for three hours". In Czech, the present indicative is used and is directly translated as "I do this for three hours".Free quote
There are also sometimes second forms of certain verbs (like to go, to do, etc.) that indicate a habitual or repeated action. These are known as iterative forms. For instance, the verb jít (to go by foot) has the iterative form chodit (to go regularly).
There is also no tense shifting (as in reported speech). E.g. "He loves her" -> "He said he loved her", the time is shifted from present to past. In Czech it is "Má ji rád" -> "Řekl, že ji má rád". The "má rád" implies present tense in both cases.
The conditional is something of an oddity, with no real indication of time. It is the same regardless of whether the action discussed is a future, present, or past action. The conditional is formed by using the auxiliary "conditional marker" and the past tense of the root verb. The condition marker appears as follows:
I would have: bych
you would have: bys
he would have: by
she would have: by
we would have: bychom
you (plural) would have: byste
they would have: by
So, "I would have gone" would be translated as "Já bych šel" (or, more usually, "Šel bych").
The future tense is another fickle part of Czech grammar. Often, verbs that appear to be present tense are actually future tense. For instance, the verb "vyhodit" (throw out) appears like a normal present tense, but actually indicates a future action. This form of the verb has no present tense — it indicates a completed action (perfective aspect), so a present tense wouldn't make sense: either the action is already completed (past) or yet to be completed (future). A different form, "vyhazovat", indicates an ongoing action (imperfective aspect) and has all three tenses.