Your lack of Italian should be little issue. I would however learn some basic phrases (hello, thank you. please, etc.) and if you will have a working phone Google Translate can help in a pinch, but just being able to search the name of a dish on google and get an English description helps a lot, even just to translate a key word to see what kind of meat or fish, for example. They likely will have an English menu, thanks to translation apps, but I find them only marginally helpful, get an Italian menu as well, believe me, you know many Italian dishes by their Italian name, not some weird translation.
Many places you will not need a reservation, or if a place looks good, inquire earlier in the day, or the day before and reserve a time. Otherwise, walk in, find a waiter or the owner, and look like you need a table, they will either seat you or indicate to pick a spot. If you want to sit somewhere specific, just point.
Now for what you did not ask. Once you sit and peruse the menu, they may bring bread, your paying for it, but it is fine. Order a bottle of water, still or sparkling (With Gas) for the table, everyone does, it is almost expected that you will. Wine is up to you, need not be a bottle, they always have house wines by the glass or carafe, always very good. There are great gems on the antipasti section, order at least one. For your main dish, you need not get both a Primi and Secondi, one or the other is fine. Do consider a vegetable side dish (Contorni), wonderful fresh grilled, steamed, or sautéed veggies. Dessert is up to you, we often split one. They will always offer coffee after, it takes some convincing them if you do not want it, it seems to be a sin in Italy to not have an espresso after dinner, a digestif (Grappa, Amaro, or other liquor) is an acceptable alternative.