Planning buy myself some winter wear. Have no clue how to proceed.

27 M here. Honestly have realised that my cloth collection is quite underwhelming and I plan to get an upgrade. After some looking around on the internet and inputs from GF and others, I plan to buy an overcoat, a muffler, a denim jeans and a pair of sneakers. Have never taken grooming seriously and this the first time I am planning to go on a shopping expedition (sort of..hehe). GF studies abroad and she isn't here to make things easier for me. So I might have to do it by myself. I am clueless. But we all have to start somewhere I guess. So I need suggestions from you guys! I am new to the city, where should I go for shopping? Are there any flea markets here? How should I approach buying clothes for myself. Budget is decent. I can spend adequately where I feel the money is worth the thing. Help me guys I am a but clueless here🥲.