Open trading account 
What is a Trading Journal? It can have many forms, but as a minimum, I believe you should record
- each trade, give it a number
- market, e.g. EURUSD
- reason why you took this trade, this can be just a system name or a more (e.g. what price action, if there was a key level, what indicators showed, what was the trend, higher timeframe trend, etc.
- chart screenshot at a moment you placed an order, i.e. how the market looked like when you decided to trade. You can also add a higher timeframe chart, too. This is a chart you will look later on to asses if this was a high quality trade, in line with your system, or not
- chart screenshot at a moment the position was opened, i.e. order was filled. Of course, if you opened at market, this is the same chart as "when you placed an order". But if I used limit or stop order to enter, it will be different.
- chart screenshot at a momemt the position was closed, either at loss or profit, OR, if you deleted the order before it was filled.
- learning, i.e. your comment on what you learned from this trade, e.g. "do not trade against ther higher timeframe trend", etc.
- assessment, i.e. was it a high quality trade or not. Based on your system / strategy / method. Your trading system tells you if and when to trade. Here you assess if you traded in line with the system or not. Also, did you manage and close the trade in line with your strategy (e.g. set & forget, or take profit half the position and trail the rest, etc.)
- trade outcome in your account currency, i.e. the loss or gain.
The above is minimum, but there is more you optionally can do
- charts showing how you managed the position, e.g. moved the stop in the direction of the trade (you never move it against the trade)
- trade outcome in pips
- date of open and close, day of the week
- any additional criteria to mark in the journal, such as trend, level (yes/no), price action (what kind of, e.g. pin, engulfing, outside bar, inside bar, etc.)
- position size and position sizing method used (e.g. equal dollar risk per trade)
- anything else you can find useful (but do not overdo becasue then there is a risk you will not have discipline to maintain all data, I suggest you start small)
- profit factor viz. risk to reward ratio (e.g. for individual trades and accumulated over number of trades)
