example.tex

\documentclass[border=10pt]{standalone}

\usepackage{tikz}
\usetikzlibrary{timeline}

\begin{document}

\begin{tikzpicture}[timespan=Day]
% now we have days as reference
% default timespan is Week

\timeline{8} % number of weeks/<timespan>

% put here the phases
\begin{phases}
\initialphase{involvement degree=1.75cm,phase color=black}
\phase{between week=1 and 2 in 0.1,involvement degree=2.25cm}
\phase{between week=1 and 2 in 0.5,involvement degree=3cm}
\phase{between week=1 and 2 in 0.9,involvement degree=2.125cm}
\phase{between week=3 and 4 in 0.7,phase color=blue!80!cyan}
\end{phases}

% put here the milestones
\addmilestone{at=phase-0.90,direction=90:1cm,text={Initial meeting},text options={above}}
\addmilestone{at=phase-0.270,direction=270:1cm,text={Initial meeting},text options={below}}

\addmilestone{at=phase-2.110,direction=120:1.5cm,text={Research},text options={above}}
\addmilestone{at=phase-2.250,direction=240:1.5cm,text={Need Agreement},text options={below}}
\end{tikzpicture}

\end{document}