Create a MT4 Indicator based on MACD and adding buy/sell arrows for another existing indicator

This project has 2 parts:

Part 1: MACD indicator

How indicator works:

When MACD line cross the zero line from below (down to up / upwards direction), it is a buy signal, so there should be a buy arrow at the price bar on the chart AFTER the CLOSE of the current candle

The indicator (one ex4 file) should also have a small window at the bottom (i.e. a separate window to the price chart) that shows only the MACD line and the zero line (other lines are not needed)

Needs to have input options such as mobile, email and pop up notifications when there is a buy/sell signal.

Part 2: Editing an existing indicator

I have an existing indicator, when placed on the price chart, and it is in the form of a histogram. When histogram changes from green to red, and closes in the red, add a sell arrow on the price chart. When histogram closes from red to green, add a buy arrow on the price chart. It should also have the same notification feature as above. I will provided this Mq4 file.

Let me know if you have any questions