Congrats! You've finished your coffee-table. If you liked building it and are happy with the result you can find other similar designs at www.screwed-up.com. If you want to know what's going on with Screwed-Up you can join the facebook page (https://www.facebook.com/Screwed-Up-2092172627662047/), or maybe you want to follow me on pinterest (https://nl.pinterest.com/screwedupdiyfurniture/pins/). For finishing touches I recommend sanding the edges and corners smooth. Also treating the top with a (clear) wood finish to protect against spills is never a bad idea.
Once the vinegar solution dries (or if you decided not to do the solution) you can go ahead and stain the project. First use a rag or air compressor to remove any dust from the table. Then use a clean rag to apply the stain of your choice. Don't forget to wear gloves and ventilate the area. Have a brush in your other hand to stain hard to reach areas.
Please read through the entire plan and all comments before beginning this project. It is also advisable to review the Getting Started Section. Take all necessary precautions to build safely and smartly. Work on a clean level surface, free of imperfections or debris. Always use straight boards. Check for square after each step. Always predrill holes before attaching with screws. Use glue with finish nails for a stronger hold. Wipe excess glue off bare wood for stained projects, as dried glue will not take stain. Be safe, have fun, and ask for help if you need it. Good luck!