There is an infinitival form that ends with the suffix -at if the stem ends in a consonant and in -lat when the stem ends in a vowel. Examples: samvolat (to break) and kaffat (to crush).
The past tense singular is formed simply by dropping the infinitival suffix -(l)at. Example: Me samvo (it broke). However since words are not allowed to end on certain consonants or clusters there is sometimes an -e added to the end. Check the page on epenthesis for more details on this.
The present tense has more variation between persons.
For verbs where the stem ends on a vowel we have the following forms using the verb dothralat, "to ride":
As you see it's the first person singular and plural that deviate a little from the others.
Examples where the stem ends in a consonant will be added when they are known.
The future tense is formed by adding a prefix to the present tense conjugation. For verbs that begin with a vowel the prefix /a-/ is added and for verbs that begin with a vowel the prefix is instead /v-/. This means that the phrase "I will ride" would be anha adothrak and "you will ride" would be yer adothrae in dothraki.