EA should do the following:

When the trend line changes from red to green => buy signal

Open buy order

When the trend line changes from green to red => sell signal

Open sell order

Control number of open orders for the defined number of hours

It would be also nice if a new order is opened by the EA when a red or green arrow appears on a chart (which is strong confirmation of the new trend).

Ideally it should be an option (order is open when red - sell  or green - buy arrow appears or just when the trend line changes the color)

EA should have input parameters (at minimum):

Number of hours (to control maximum number of open orders during this number of hours; if value 0 - not used)

Maximum number of open orders (Maximum total number of opened orders in the defined "Number of hours"; if value 0 - not used)

Magic number (to be entered)

Lot size (default size for orders that are opened, starting from 0.01)

Total number of Lots (Maximum number of lots for all trades that were opened in the time defined by "Number of hours"; if value 0 - not used)