Also, fun fact! Not all tides here are a simple "up, then down"!
This is a bit of the south coast of England. The main bit of water is the English Channel. The narrow bit full of very very strong tide arrows is called the Solent.
This is an example tidal curve for Southampton, a city in the top left corner of the above chart. The red curve shows water level in metres above its lowest level, measured when the tide is in the extreme (spring) part of its fortnightly cycle.
Most places have a high tide, then 6 hours later is low tide, then 6 hours later is high tide, and on and on (fudged a bit as the full cycle is around 12.5hrs not 12hrs). The chart looks kind of like a sine wave. Southampton and some other places on the south coast do not have that. There is high tide, then a little bit of water goes out, then it comes in again for another high tide (which can be higher or lower than the first one), then allllllllllll the water ebbs out in about 3hrs (this is stupidly fast), then there is low tide. Then the water comes in for a couple hours, then slows or stops or reverses entirely for a couple hours, then climbs to the first high tide again.
Southampton is an important port city and the Solent is one of the busiest waterways in the world. Good luck.