EQ to me is one of the most important aspect of a song. Its hard to understand at first but once you get it your songs are gonna sound so much better. EQ lets you place every element in its place. A good comparaison I heard once was to compare a song to a box. You can only fit so much in it. Without proper EQ your box will be too full or just empty. EQ lets you take some frequencies off where an element doesnt need them. For example, your bass will need less high frequencies than your hats. So you will cut off the highs on your bass with an EQ. And you will cut of the lows on your hats with EQ. You can also use it to boost some frequencies but I would start by only removing those you dont want. As a general rule of thumb you want your bass and kicks to have lower frequencies (50-150), then comes the snares (200-300) then the hats and claps. Respectively called lows, mids and highs. EQ is what will make your song ''smooth''. Everything will fit just right togheter.
Another comparaison I came with myself is like if you cook a dish. The EQ is how you use your seasoning (frequencies). You dont want too much, nor too little. The flavors need to come togheter just right.
Hope I wasn't too confusing. Experiment away, only with time you'll understand this amazing tool.