We go somewhere. We eat something. We speak with someone. Then one small change lets Japanese describe not only the action — but the desire behind it.
Japanese can now move beyond describing what you do. With 〜たいです, you can begin describing what you want to do.
Listen first. The action remains familiar. What changes is the speaker's relationship to it.
勉強します describes the action. 勉強したいです adds your desire to do it.
At this stage, you do not need a large conjugation table. Use the familiar ます form as your starting point.
〜たいです does not erase your earlier Japanese. It joins it. Places, companions and times can now become part of what you want to do.
A question about desire is different from asking what someone usually does. It invites them to talk about what they would like to do next.
The question word changes, but 〜たいです stays in place.
Change 〜たいです to 〜たくないです when you want to say that you do not want to do something. For now, that single negative pattern is enough.
IJ-0085 taught you how to ask why. Now that question can reach into what someone wants to do.
The question is simple. The answer can begin to sound like you.
In each exchange, A is the female voice you have already heard. B answers with a different male voice.
“Knowing what someone does tells you about their day. Knowing what they want begins to tell you about them.”
You can now describe an action, place it somewhere, give it a time, share it with someone, explain how often it happens, say how long it lasts, give it a beginning and end, explain why — and now say whether you want it.
WHAT → WHERE → WHEN → WITH WHOM → HOW → HOW OFTEN → HOW LONG → FROM / TO → WHY / REASON → WANT / INTENTION
Look at an ordinary day ahead of you. Choose one thing you genuinely want to do. It does not need to be impressive.
Perhaps you want to drink coffee somewhere quiet. Perhaps you want to walk. Perhaps you want to speak Japanese to one person. The grammar is small. The answer is yours.
Where do you want to go? What do you want to learn? Who do you want to speak with?
Sometimes a future begins with nothing more complicated than 〜たいです.