In learning any language there are certain verbs (almost always irregular and difficult ones) that are essential to learn early on. The most important are the words for 'to be', 'to go' and 'to have'. This is because those verbs are used so often both individually, but also because they can be combined with other verbs to make different tenses - past, present or future.
For example, using the verb 'comer' ('to eat') -
I am eating (present, using 'to be') - estoy comiendo
I was eating (past, using 'to be') - estaba comiendo
I am going to eat (future, using ' to go') - voy a comer
I have eaten (past, using 'to have') - he comido
These compound forms are not the only ways to express the past present or future, but they are extremely useful. It is also useful to learn the past participle (e.g eaten/comido) and present participle (e.g. eating/comiendo), but that is something I will cover in another post.
In Spanish there are five verbs to learn, as there are two words for 'to be' and two words for 'to have'.
ir = to go
ser = to be
estar = to be
tener = to have
haber = to have
I have recently covered some of the differences between ser and estar. Over the next few days I will cover some of the differences between haber and tener.