Hi Nicholoas,
When you install an EA onto the chart the first thing you always do is to make sure the chart and the timeframe match up with the EA. Instead of looking up at the upper left corner of the chart you can also look at the chart tab.
If you have multiple charts open in metatrader and you select a different chart by clicking on the chart tabs this does not close the chart. However, if you right click on a chart tab and select Close this will close the chart. When the chart is closed the Expert Advisor will not longer be working.
If you want to stop one Expert Advisor from running and allow others to continue to run you have two options. You can delete the Expert Advisor from the chart or you can right click on the smiley face or blue hat in the upper right corner of the chart and Expert Advisors, properties, and Common. Then you can uncheck Allow live trading.
At the end of the week if you want to install new Expert Advisors you can right click on the smiley face or blue hat in the upper right corner of the chart, select Expert Advisors, and then select Remove. Now you can install the new Expert Advisor. If you have open trades you have the option to continue to let them trade until they close by themselves or you can go ahead and close them after the markets open on Monday.