Most verbs in Arabic are built around a trilateral root, consisting of three consonants. For example, the word دَخَلَ (dakhala) which means “to enter”. The root of the word is د + خ + ل . The consonants will remain the same, no matter what tense the verb is in. As in Spanish, verbs in Arabic are conjugated (change form, depending on pronoun). In the “present” tense, it works like this, with use of a prefix (ت - “ta” , ي - ya, or ن - na) along with modifying the vowel pattern. The root consonants remain the same. The following example is in the “past” or perfect tense, with a suffix attached to the root.
He entered - دَخَلَ (dakhala)
She entered - دَخَلَتْ (dakhalat)
You (m. sing.) entered - دَخَلَتَ (dakhalata)
You (f. sing.) entered - دَخَلَتِ (dakhalati)
I entered - دَخَلَتُ (dakhalatu)
They (dual m. - 3rd person) - دَخَلا (dakhala)
They (dual f. - 3rd person) - دَخَلَتَا (dakhalata)
You (dual 2nd person) entered - دَخَلْتُمَا (dakhaltuma)
They (m. pl) entered - دَخَلُوا (dakhalua)
They (f. pl) entered - دَخَلْنَ (dakhalna)
You (m. pl) entered - دَخَلْتُمْ (dakhaltum)
You (f. pl) entered - دَخَلْتُنَّ (dakhaltunna)
We entered - دَخَلْنَا (dakhalna)

Arabic does not have an exact equivalent of the “present” and “past” tense, as used in English. Instead, it has the “perfect” and “imperfect” tenses. Perfect tense is used to describe actions that have been completed, such as “he ate” but not “he was eating” which is imperfect (incomplete action in the past or present). The above example is the perfect tense, describing completed actions in the past. The above is also in the “active” voice (”he entered”), rather than “passive” which would be “he had entered”.

When looking up words in the dictionary, verbs are given in the male singular third person (”He”), in the perfect tense. For example, you would find “to enter” listed as دَخَلَ (dakhala).